Modern railroad tracks are constructed using long sections of ribbon rail. The sections are often found in lengths up to about 1700 feet but can range up to 2000 feet or longer. Shorter sections of lengths as little as 300-320 feet are also available. These sections of ribbon rail are formed by butt-welding multiple sticks of rail, which traditionally come from a steel mill in thirty-nine foot or seventy-eight foot lengths. The welding of the ribbon rails is done at a welding plant and the welded ribbon rails are transported to their installation site on a specially constructed rail train. When existing track is being replaced, ribbon rails may be unloaded from the rail train using a rail unloading machine, such as the rail unloading machines disclosed in U.S. Pat. Nos. 6,981,452 and 7,707,943, both to Herzog et al. The rail-unloading machine pulls one or two rails off of the rail train as the rail train moves down the existing track and lays it alongside the existing rails.
Prior art rail trains traditionally comprise a plurality of sixty-foot-long flatcars connected together by standard railroad couplers. Each car includes a pair of transverse stands for supporting the ribbon rail. The stands of each car are spaced 30 feet apart and 32 feet from the respective coupler such that the stands are spaced 30 feet apart along the length of the rail train. The stands each include multiple tiers (typically five or six tiers) which each support a plurality of rails, for example, eight to twelve rails per tier. The space in which an individual stick of rail is supported on each shelf may be referred to as a pocket. The stands must each be strong enough both to support the weight of the rails and to resist side loads created by flexing of the ribbon rails as the rail train traverses curves in the track. Sidewalls of each stand constrain the rails on the shelves. Thirty-foot spacing of the stands is believed to be optimal for supporting the rails without excessive sagging of the rails between the stands.
The rails are loaded or threaded onto the rail train and across the shelves of the racks by a powered drive system. Considerable effort is required to carefully thread each rail into a desired pocket on each shelf. Loading the first rail on each shelf is the most difficult as it is difficult to thread the rail through a desired pocket of each rail support shelf, particularly when the rail train is sitting on a curved section of track as the end of the rail wants to move in a straight line and the leading end tends to sag.
A common practice to assist in guiding a rail through the selected pocket on the rack car shelves is to mount a pointed shoe on the end of each rail, but it is still difficult to keep the stick of rail traveling in a curved path if the train is curved. Once the first rail is loaded on each self, a guide arm can be attached to a shoe mounted on the leading end of the next rail to be loaded with the guide arm having a receiver positioned over the head of the previously loaded rail. The receiver slides along the head of the previously loaded rail as the next rail is loaded so as to guide the end of the rail being loaded in alignment with the desired pocket of each shelf and to maintain proper spacing between the rail being loaded and the previously loaded rail. Because there is not a previously loaded rail to use in guiding the first rail in place, workers may have to use pry bars and the like to manually redirect the end of the rail through the desired pockets and prevent the end of the rail being loaded from extending into another pocket or outside of the sidewall of the support rack across which it is being loaded.
At least one car in each rail train is a tie-down car including a specialized stand that includes means for fixing the rails to the racks to prevent longitudinal movement of the rails relative to the tie-down car. The fixing means generally includes a plurality of clamping blocks that are bolted to the stand on opposite sides of each rail so as to bear against the foot or base flange of the rail and clamp it against the stand. Typically each clamping block is held down by three or four large bolts which must be installed or removed using an impact wrench or the like. All the other racks in the train allow for relative longitudinal movement of the rails and may include rollers that support the rails. This relative movement between the racks and the rails is required in order to allow the rails to flex without stretching or compressing as the train traverses curves in the track, as well as to allow for coupler slack that exists in each of the couplers between cars.
Each coupler has up to approximately six inches of slack. Coupler slack may necessitate that the tie-down car be positioned near the center of the rail train so as to evenly divide the rails and to thereby insure that neither the forward end nor the rearward end of the rail can move a sufficient distance relative to the nearest adjacent rack that the end will fall off of the rack.
There remains a need for an improved system for guiding rails being loaded onto the cars of a rail train and in particular onto the rail rack cars of a rail train.